Re: different when dealing with a wave sound

[Juan Pablo Carbajal]

On Tue, May 13, 2014 at 2:19 PM, Stephen Zhang <address@hidden> wrote:
> Thank you for replaying me. I did it again just now, it was the same the
> result.
> My OS is Arch Linux x86_64 with kernel 3.14.2. My Octave version is 3.8.1
> with "Signal" package version 1.3.0, "General" package version 1.3.4 and
> "Control" package version 2.6.4.
> I did test other wave files just using wavread() and wavwrite(), it works
> fine.
> I didn't get any warning or error when doing wavwrite(), as you can see
> here[1].
> The output file can be downloaded here[2].
> Thanks.
>
> [1]http://imagebin.org/310671 (this link may be invalid some time later)
> [2]http://pan.baidu.com/s/1bnAI6ar
>
>
>
> 2014-05-13 14:39 GMT+08:00 Juan Pablo Carbajal <address@hidden>:
>>
>> On Mon, May 12, 2014 at 6:15 PM, Stephen Zhang <address@hidden> wrote:
>> > Hi, all
>> > I have a wave sound here[1], which mixed a man's sound with some "beeee"
>> > sound. I tested this sound in matlab(windows version), octave(windows
>> > version) and octave(linux  version), but get diffenrent result. Details
>> > are
>> > here:
>> > I use these commands:
>> >
>> > [wav fs bps] = wavread('buzz.wav');
>> > b = fir1(50, [X Y], 'bandpass');
>> > y = filter(b, 1, wav);
>> > wavwrite(y, fs, bps, 'test.wav');
>> >
>> > When I set X=0.3, Y=0.7 (in line 2),In matlab and octave(windows
>> > version), I
>> > can clearly hear the man's sound saying "zhe li shi dian zi ke ji da
>> > xue"(Chinese) without any "beeee" sound while in octave(linux version),
>> > I
>> > can only hear "beeee" sound. Only when I set X=0.8 and Y=0.99 can I hear
>> > the
>> > man's sound(not very clearly) with "beeee" sound in octave's linux
>> > version.
>> > I'd really like to know what causes difference? Is it a bug or just my
>> > fault?
>> >
>> > Thanks a lot to read this email.
>> > Regards,
>> > Stephen
>> >
>> > [1]http://pan.baidu.com/s/1dDtcTwt
>> >
>> > _______________________________________________
>> > Help-octave mailing list
>> > address@hidden
>> > https://lists.gnu.org/mailman/listinfo/help-octave
>> >
>>
>> I can't reproduce. Without filtering I hear the annoying sound, when I
>> run your code with X=0.3, Y=0.7 I hear a male person speaking.
>> What version of Octave(linux) and signal package are you using?
>> What OS?
>> Do other wav files play fine?
>> Do you get any warning when doing wavwrite?
>
>

Stephen please answer at the bottom of the messages.

Indeed your test.wav file has just the buzz on it. Try plotting the
output of the filter operation and check if it is really filtering
something. I got this image
http://picpaste.com/Screenshot_from_2014-05-13_16_07_42.png

doing

figure(1)
subplot(2,1,1)
plot(wav)
subplot(2,1,2)
plot(y)
axis tight
axis([0 length(wav) -0.1 0.1])